The present invention relates to wastewater treatment systems, and more particularly to a wastewater treatment system using seawater and hydrogen peroxide for treating household wastes in reaction chambers and discharging the treated wastewater into receiving tidal seawater.
The present system is particularly adapted for use with small communities which are seaside or located near tidal basins where heretofore wastewater was dumped directly into tidal waters. The system is particularly adapted for areas where fresh water is not plentiful and seawater is used for flushing waste from household systems. Previously known wastewater treatment processes have used septic tanks with sand filters and chlorinators, septic tanks with leach beds for ground disposal, mechanical aeration means, including mechanical air blowers, transfer pumps and complex agitation schemes to rapidly decompose the water borne waste and special toilets with incinerators, holding tanks, equipment for recycling or treatment and recirculating, composters, and chemical disinfectants and deodorizers. Whereas most of these commercially available versions are well conceived and designed, the results they achieve when installed require favorable conditions. In coastal communities where the availability of fresh water becomes a problem, it may be necessary to rely on seawater for flushing toilets. This introduces an unacceptable probability of failure in conventional biochemical decomposition processes because of toxic shock loading of the biological system if large volumes of seawater and fresh water are charged alternately. The high salinity discharge damages leaching fields and sand filters by reducing porosity and adsorptive capacity. When septic tanks are used, a high sodium ion and chloride ion content of the seawater-based effluent degrades the adsorptive capacity of a soil filtration medium.
Other problems of significance relate to the locations and general accessibility of seaside and other tidal communities. Often these communities are built on islands which are not accessible by land and this creates problems in transportation of both materials and equipment. Other problems include inadequate soil for leaching or sludge disposal purposes and the general character of the terrain which makes installation and maintenance of complex systems a difficult problem.
The present system is adapted for use in small summer vacation communities which are located adjacent to tidal seawater and which use such water for waste disposal. One example is MacMahan Island which is located in the Sheepscot Bay area of Maine. This community includes approximately forty (40) privately owned cottages and has a peak population during the summer vacation months. The island terrain is rocky and the soil cover is generally shallow and inadequate for septic tank operation or sludge disposal. Seawater is used for flushing toilets in the cottages to conserve fresh water, the supply of which is provided by deep wells and is limited during peak seasonal demand times. Transportation access to the island is by water craft only.
The cottages are equipped with incoming salt water and fresh water service lines and with sewage discharge lines to the shore. Seawater is pumped in at a single location from below the tidal shore into an elevated storage tank on the island and transmitted on demand to the individual cottages for flushing toilets and other waste removal. This reduces the demand for fresh water which is supplied from a separate source and required for drinking, cooking, and so forth. Because of the location of the island, the discharge of untreated waste into the surrounding tidal waters would cause severe health and environmental problems.
To overcome these difficulties, the waste treatment system of the present invention has been developed. The system includes a source of seawater which is preferably stored in a large tank or container. Not only is seawater plentiful in tidal areas, but it also includes natural microbia and aerobic microorganisms which aid in the decomposition of solid waste materials. Hydrogen peroxide is added to the stored seawater and the mixture is designed to be fed to individual households using a gravity or pump feed arrangement. The hydrogen peroxide provides a disinfecting capability to the mixture as well as being a source of oxygen. The activated seawater is fed directly into the waste treatment systems of the individual cottages or households and is used to flush toilets and to aid in carrying away other gray matter wastes from the kitchen, washwater, and so forth. The outlet pipes from the cottages containing the activated seawater and wastes are fed to a treatment location, including a series of two or three drum reaction containers. The outlet of these reaction containers is fed into a filter container which distributes the wastewater over a filter bed which removes any residual impurities. The filtered water is then discharged to the tidal water as an odorless disinfected liquid which has no adverse affects upon the environment. The system includes a bypass line which feeds activated seawater directly from the storage tank into the reaction vessels thereby providing a continuous aerobic biochemical reaction and solids separation independent of the useage of the household waste systems.
Among the objects of the present invention are a provision of a wastewater treatment system particularly adapted for seaside or other tidal communities where fresh water and commercial sewage treatment facilities are limited. Another object of the present invention is to provide a wastewater treatment system which can be used in individual households and which is inexpensive to install, maintain, and operate.